Closed ink reservoir for recording instruments



p 10, 1968 P. SCHEUZGER ET AL 3,401,402

CLOSED INK RESERVOIR FOR RECORDING INSTRUMENTS Filed May 10, 1967 II IIIIILI-'.

United States Patent 3,401,402 CLOSED INK RESERVOIR FOR RECORDING INSTRUMENTS Peter Scheuzger, Highland Park, and Marshall S. Joseph and Hiroshi Ono, Chicago, Ill., assignors to Victor Comptometer Corporation, Chicago, 111., a corporation of Illinois Filed May 10, 1967, Ser. No. 637,591 7 Claims. (Cl. 346-440) ABSTRACT OF THE DISCLOSURE Closed link reservoir for recording instrument's, comprising rigid molded polyethylene tray, thin flexible fluorohalocarbon plastic membrane heat sealed marginally to upper edge of tray and generally conforming to interior shape of tray when collapsed with reservoir empty, heavier cover film overlying and marginally heat sealed to flexible membrane for absorbing shock loads encountered in shipping and handling and as barrier to water vapor transmission from ink and perforated to subject membrane to atmospheric pressure in use, and bottom film heat sealed to base of tray for additional protection against ink coagulation, with snap-fit retention of reservoir in instrument and a two-part shipping container having one part formed to receive the (reservoir and the other part formed to receive a pressure pad for absorbing shocks, vibrations and stresses incurred in shipping and handling to prevent resultant rupturing of the reservoir.

Background of the invention Field of the invention-This invention relates generally to graphic recorders, and more particularly to an improved closed ink reservoir for supplying ink to pen means used therein.

Description of the prior art.Means for supplying ink to pen means in recording instruments are of various types, usually open, being employed. Specifically adapted for use in high speed graphic communication system recorders, wherein the pen moves omnidirectionally over a recording medium and is subject to high speed operation with rapid acceleration and deceleration and to periodic interruptions in its engagement with the record medium, is the means disclosed in copending application for United States Letters Patent Ser. No. 582,729, filed Sept. 28, 1966, which is a combination pressure and capillary system Comprising a closed flexible bag or sac connected by non-capillary conduit means to capillary conduit means connected to the pen. Such closed flexible bag or sac type reservoirs provide greatly improved performance capabilities over open systems, but they also have their own problems. Most serious, especially with respect to shelf life, is that of ink coagulation resulting from loss of water vapor from the ink through the plastic film of the bag. The characteristics of low permeable plastic films suitable for such ink sacs or bags result, as resistance to permeability of liquids and gases increases, in stiffness and hardness increasing, flex life decreasing, heat sealing becoming more diflicult, and stress cracks with ensuing leakage problems being caused by double folding.

Unless such ink sacs or bags are small, difficulties in manufacturing, filling, shipping, and installing are encountered, and to minimize leakage problems, rough handling must be avoided. The flexibility required for them to perform their function further compounds the difliculties presented because of the resulting limitation on the thickness of the film of which they may be constructed.

The larger area per volume ratio of such small ink pressure" or capillary systems i 3,401,402 Patented Sept. 10, 1968 sacs or bags and thinner walls, as compared to ink supply bottles used as reservoirs in open systems, makes their shelf life very much less than that of a supply bottle, and their relatively small volume of ink makes more frequent replacement necessary. Since most often replacement of such bags or sacs requires the use of servicemen, the otherwise distinct advantages of a closed ink system are somewhat balanced out.

Summary of the invention This invention overcomes the disadvantages of such prior ink sacs or bags, while enabling the superior closed ink system to be employed, by providing a novel closed ink reservoir having maximum resistance to water vapor transmission or permeability with resulting maximum shelf life, and also a very high degree of flexibility to assure uninterrupted capillary supply of ink to the pen. The invention also comprehends a large volume reservoir, maximum resistance to rough handling in shipment, and greatly simplified installation and replacement. In the specific embodiment herein illustrated, the reservoir comprises a rigid molded polyethylene tray having snap-fit engagement with the recording instrument, a thin flexible fluorohalocarbon plastic membrane heat sealed marginally to the upper edge of the tray and generally conforming to the interior shape of the tray when collapsed with the reservoir empty, a heavier cover film overlying and marginally heat sealed to the flexible membrance for absorbing shock loads encountered in shipping and handling and as a barrier to water vapor transmission from the ink and perforated to subject the membrane to atmospheric pressure in use, and a bottom film heat sealed to the base of the tray for additional protection against ink coagulation, with a twopart shipping container having one part formed to receive the reservoir and the other part formed to receive a pressure pad for absorbing shocks, vibrations and stresses incurred in shipping and handling to prevent resultant rupturing of the reservoir.

'In the drawings:

FIGURE 1 is a top plan view of a portion of a recording instrument showing a closed ink reservoir embodying the features of this invention mounted therein;

FIG. 2 is an end elevation, as seen from the lower side of FIG. 1, with parts in section;

FIG. 3 is an enlarged detail vertical section through the reservoir taken substantially on the line 33 of FIG. 1; and

FIG. 4 is a vertical section through a shipping container housing the reservoir.

Referring more particularly to FIGS. 1 and 2, reference numeral 11 indicates in general a recording instrument of well-known construction which includes a cantilever type of pen support 12 for a pen nib 13 (FIG. 2) supplied by a capillary tube 14 which extends through the pen support 12 and is connected to one end of a supply tube 15 of somewhat larger diameter. The recording instrument 11 also includes a writing platen 16 supported in well-known manner by posts 17 in parallel spaced relationship above a base plate 18 (FIG. 2) from which a vertical anchor pin 19 extends upwardly adjacent one side of the instrument, as seen at the top of FIG. 1.

A recording instrument of this type is disclosed in copending application for United States Letters Patent Ser. No. 582,729, filed Sept. 28, 1966 wherein all of the parts are the same as those heretofore described, except for the anchor pin 19. As is well understood in this art, the pen 13 is moved into and out of engagement with paper or any other suitable recording medium disposed on the platen 16 and moves omnidirectionally thereover at high speed with rapid acceleration and deceleration. In said application Ser. No. 582,729, a combination pressure and capillary system is employed for supplying the pen with ink which includes the capillary tube 14 and the larger supply tube 15, as previously described herein, and a closed flexible bag or sac connected to the latter as an ink supply reservoir. The instant invention comprises an improved closed ink reservoir designated generally by reference numeral 21 for use in a recording instrument, such as that disclosed in said prior application, together with a novel shipping container for that reservoir to be described hereinafter. 1

As best seen in FIG. 3, the reservoir 21 comprises a rigid molded polyethylene tray 22 having a threaded inlet nipple 23 formed integrally therewith adjacent one corner and, as shown in FIG. 1, integral snap-fit means 24 formed at its other end as outwardly extending protuberances separated from each other to define a horizontally disposed V-shaped notch 25 communicating with an apertured slot 26 for frictionally engaging the anchor pin 19. The width of the tray 22 is such as to conveniently pass between adjacent platen mounting posts 17 to permit snap-fit engagement of the means 24 with the anchor pin 19 to retain the tray and the reservoir 21 in its operative position of FIG. 1 on the base plate 18 below the platen 16.

As shown in FIGS. 1 and 2, the inlet nipple 23 of the tray 22 is adapted to be connected by a suitable coupling 27 to the end of the supply tube remote from the pen 13. It will be understood that prior to installation of the reservoir 21 in the recording instrument 11, a suitable cap 28 (FIG. 3) will be mounted on the nipple 23, and that this will be removed and the coupling 27 connected to the reservoir when it is to be placed in the recording instrument.

A thin flexible membrane 29 with a low permeability to moisture or water vapor contained in the ink employed is molded to substantially the same contour as that of the interior of the tray 22 with its marginal portions conforming to the upper edges of the tray. It has been found that the most satisfactory material for this membrane 29 is a fluorohalocarbon plastic with a thickness of approximately one mil. Interposed between the marginal portions of the membrane 29 and the upper edges of the tray 22 is a laminated fluorohalocarbon-polyethylene gasket 31 (FIG. 3) which facilitates heat sealing of the marginal portions of the membrane 29 to the tray 22.

To enable the use of such a thin membrane 29, which facilitates capillary feeding of ink to the pen nib 13, a backing plate or heavier cover film 32 of fluorohalocarbon plastic, preferably five mils in thickness, is disposed across the top of the tray and marginally heat sealed to the membrane 29 in well-known manner. And for further protection against loss of water vapor from the ink in the reservoir 21, a fiuorohalocarbon-polyethylene laminated film 33 may be heat sealed to the bottom of the tray 22.

With this reservoir in its original empty condition as shown in full lines in FIG. 3, filling thereof by introducing ink through the inlet nipple 23 will result in the thin membrane 29 being pressed upwardly against the cover plate or film 32. As illustrated in broken lines in that figure, this will result in the membrane 29 assuming some random folds, but the cover film 32 will function as an effective guard against loss of water vapor from the ink. This cover film 32 is perforated at one or more places at 34 (FIGS. 1 and 3) to provide direct access of atmospheric pressure to the membrane 29. Thus, as the ink is supplied to and used by the pen 13, the function of the capillary tube 14 during such feeding of the ink will be facilitated. It will be understood, of course, that the maximum flexibility of the membrane 29 thus provided will assure the desired ink feeding. It also will be appreciated that membrane 29 alone would have insufficient resistance to permeability of the water vapor in the ink during handling or movement of the reservoir, but the cover film 32 effectively backs up the membrane 29 to so increase the resistance to water vaporpermeability that the reservoir 21 has a very long shelf life expectancy. This is enhanced by the use of the bottom film 33, and it will be appreciated that prior to installation of the reservoir 21 in a recording instrument and after it has been filled with ink, it is preferred that a temporary sealing tab of suitable film material be placed over the perforation or apertures 34 in the cover film 32.

When it is desired to install an ink reservoir 21 in the recording instrument 11, the shipping cap 28 is removed and the reservoir secured to the free end of the supply tube 15 by means of the coupling 27. The closed ink reservoir then may be elevated approximately one foot above the recording instrument to initiate ink flow through the supply tubes 15 and 14 to the pen 13. Then the reservoir 21 is placed on the base plate 18 and slid laterally between the posts 17 to engage the snap-fit means 24 with the anchor pin 19, the temporary sealing strip over the perforation or apertures 34 first having been removed. As flexibility of a film like the membrane 29 is inversely proportional to the cube of the film thickness, this thin membrane 29 allows a much higher degree of flexibility than a thicker-walled bag or sac would provide in order to assure uninterrupted capillary flow to the pen. At the same time, loss of water vapor from the ink while in operational use is less than that of the prior bag or sacs, and the cover film 32 is of even greater importance in this connection during shipment or handling of the reservoir and further assures against breakage or rupturing of the thinner membrane 29.

FIG. 4 illustrates a shipping container specifically designed for this closed ink reservoir 21 which comprises separable lower and upper portions 35 and 36 adapted to be secured together by suitable clips, tape, or any other desired means. The lower portion 35 of this shipping container, which preferably is injection molded from a suitable polyurethane mixture, is provided with a cavity 37 in its upper surface shaped to conform to the outer contour of the reservoir 21, and particularly the tray 22. The upper portion 36 of the container preferably is made of the same material as the lower portion and is pro vided in its lower surface with a cavity 38 larger in plan than the tray 22, with a pressure pad 39 disposed therein. Consequently, when the two parts 35, 36 of the ship ping container are clamped together with the ink reservoir 21 disposed in the cavity 37, the pad 39 will be held firmly in surface contact with the cover film 32 so as to absorb shocks and vibrations attendant with shipping and handling of the reservoir-containing shipping container. This arrangement also will exert pressure on the several heat-sealed portions to permit of rough handling without rupturing the reservoir. It also will be appreciated that the resulting handling characteristics of this container and reservoir facilitate customer installation and, even if a Serviceman is employed, the relatively large ink capacity of the reservoir materially reduces the frequency of replacement.

We claim:

1. A closed ink reservoir for recording instruments, comprising a rigid tray, a thin flexible membrane of low permeability to ink substantially conformed to the inner contour of said tray and marginally sealed thereto, a substantially flat, heavier and apertured cover film marginally secured to said tray and membrane, and means providing access to the interior of said tray to enable filling thereof with ink to press said membrane into intimate contact with said cover film.

2. A closed ink reservoir according to claim 1, wherein said tray is made of molded polyethylene, and said membrane is a fluorohalocarbon plastic film.

3. In a closed ink reservoir according to claim 2, wherein said membrane is approximately one mil thick, 21 polyethylene-fluorocarbon laminated gasket interposed between the marginal portions of said membrane and said tray to facilitate heat sealing of the membrane to the tray.

4. A closed ink reservoir according to claim 3, wherein said cover film is a fluorohalocarbon plastic approximately five mils thick.

5. In a closed ink reservoir according to claim 1, a fluorohalocarbon-polyethylene laminated film heat sealed to the bottom of said tray.

6. In a closed ink reservoir according to claim 1, for use in a recording instrument having an anchor pin, snapfit means forming a part of said tray for engagement with said pin to remo'vably anchor the reservoir in the instrument.

7. A closed ink reservoir according to claim 1, having a shipping container comprising a lower portion with a cavity in its upper surface shaped to conform to the outer contour of said tray, an upper portion with a cavity in its under surface larger in plan than said tray, and a pressure pad disposed in said cavity in said upper portion to exert pressure against said cover film when said tray is disposed in said cavity in said lower portion and to absorb shocks and vibrations attendant with shipping and handling of the reservoir-containing shipping container.

References Cited UNITED STATES PATENTS 2,582,043 1/1952 Krahulec 346140 2,820,689 1/1958 Holloway 346--140 3,169,821 2/ 1965 Miller 34-6140 RICHARD B. WILKINSON, Primary Examiner.

I. W. HARTARY, Assistant Examiner; 

